/*
** $Id: ldebug.c,v 2.29.1.6 2008/05/08 16:56:26 roberto Exp $
** Debug Interface
** See Copyright Notice in lua.h
*/


#include <stdarg.h>
#include <stddef.h>
#include <string.h>


#define ldebug_c
#define LUA_CORE

#include "lua.h"

#include "lapi.h"
#include "lcode.h"
#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lvm.h"



static const char *getfuncname(lua_State *L, CallInfo *ci, const char **name);


static int currentpc(lua_State *L, CallInfo *ci)
{
    if (!isLua(ci)) return -1;  /* function is not a Lua function? */
    if (ci == L->ci)
        ci->savedpc = L->savedpc;
    return pcRel(ci->savedpc, ci_func(ci)->l.p);
}


static int currentline(lua_State *L, CallInfo *ci)
{
    int pc = currentpc(L, ci);
    if (pc < 0)
        return -1;  /* only active lua functions have current-line information */
    else
        return getline(ci_func(ci)->l.p, pc);
}


/*
** this function can be called asynchronous (e.g. during a signal)
*/
LUA_API int lua_sethook(lua_State *L, lua_Hook func, int mask, int count)
{
    if (func == NULL || mask == 0)    /* turn off hooks? */
    {
        mask = 0;
        func = NULL;
    }
    L->hook = func;
    L->basehookcount = count;
    resethookcount(L);
    L->hookmask = cast_byte(mask);
    return 1;
}


LUA_API lua_Hook lua_gethook(lua_State *L)
{
    return L->hook;
}


LUA_API int lua_gethookmask(lua_State *L)
{
    return L->hookmask;
}


LUA_API int lua_gethookcount(lua_State *L)
{
    return L->basehookcount;
}


LUA_API int lua_getstack(lua_State *L, int level, lua_Debug *ar)
{
    int status;
    CallInfo *ci;
    lua_lock(L);
    for (ci = L->ci; level > 0 && ci > L->base_ci; ci--)
    {
        level--;
        if (f_isLua(ci))  /* Lua function? */
            level -= ci->tailcalls;  /* skip lost tail calls */
    }
    if (level == 0 && ci > L->base_ci)    /* level found? */
    {
        status = 1;
        ar->i_ci = cast_int(ci - L->base_ci);
    }
    else if (level < 0)    /* level is of a lost tail call? */
    {
        status = 1;
        ar->i_ci = 0;
    }
    else status = 0;  /* no such level */
    lua_unlock(L);
    return status;
}


static Proto *getluaproto(CallInfo *ci)
{
    return (isLua(ci) ? ci_func(ci)->l.p : NULL);
}


static const char *findlocal(lua_State *L, CallInfo *ci, int n)
{
    const char *name;
    Proto *fp = getluaproto(ci);
    if (fp && (name = luaF_getlocalname(fp, n, currentpc(L, ci))) != NULL)
        return name;  /* is a local variable in a Lua function */
    else
    {
        StkId limit = (ci == L->ci) ? L->top : (ci + 1)->func;
        if (limit - ci->base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
            return "(*temporary)";
        else
            return NULL;
    }
}


LUA_API const char *lua_getlocal(lua_State *L, const lua_Debug *ar, int n)
{
    CallInfo *ci = L->base_ci + ar->i_ci;
    const char *name = findlocal(L, ci, n);
    lua_lock(L);
    if (name)
        luaA_pushobject(L, ci->base + (n - 1));
    lua_unlock(L);
    return name;
}


LUA_API const char *lua_setlocal(lua_State *L, const lua_Debug *ar, int n)
{
    CallInfo *ci = L->base_ci + ar->i_ci;
    const char *name = findlocal(L, ci, n);
    lua_lock(L);
    if (name)
        setobjs2s(L, ci->base + (n - 1), L->top - 1);
    L->top--;  /* pop value */
    lua_unlock(L);
    return name;
}


static void funcinfo(lua_Debug *ar, Closure *cl, void *plight)
{
    if (plight || cl->c.isC)
    {
        ar->source = "=[C]";
        ar->linedefined = -1;
        ar->lastlinedefined = -1;
        ar->what = "C";
    }
    else
    {
        ar->source = getstr(cl->l.p->source);
        ar->linedefined = cl->l.p->linedefined;
        ar->lastlinedefined = cl->l.p->lastlinedefined;
        ar->what = (ar->linedefined == 0) ? "main" : "Lua";
    }
    luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
}


static void info_tailcall(lua_Debug *ar)
{
    ar->name = ar->namewhat = "";
    ar->what = "tail";
    ar->lastlinedefined = ar->linedefined = ar->currentline = -1;
    ar->source = "=(tail call)";
    luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
    ar->nups = 0;
}


static void collectvalidlines(lua_State *L, Closure *f)
{
    if (f == NULL || f->c.isC)
    {
        setnilvalue(L->top);
    }
    else
    {
        Table *t = luaH_new(L, 0, 0);
        int *lineinfo = f->l.p->lineinfo;
        int i;
        for (i = 0; i < f->l.p->sizelineinfo; i++)
            setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
        sethvalue(L, L->top, t);
    }
    incr_top(L);
}


static int auxgetinfo(lua_State *L, const char *what, lua_Debug *ar,
                      Closure *f, void *plight, CallInfo *ci)
{
    int status = 1;
    if (plight == NULL && f == NULL)
    {
        info_tailcall(ar);
        return status;
    }
    for (; *what; what++)
    {
        switch (*what)
        {
        case 'S':
        {
            funcinfo(ar, f, plight);
            break;
        }
        case 'l':
        {
            ar->currentline = (ci) ? currentline(L, ci) : -1;
            break;
        }
        case 'u':
        {
            ar->nups = f ? f->c.nupvalues : 0;
            break;
        }
        case 'n':
        {
            ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
            if (ar->namewhat == NULL)
            {
                ar->namewhat = "";  /* not found */
                ar->name = NULL;
            }
            break;
        }
        case 'L':
        case 'f':  /* handled by lua_getinfo */
            break;
        default:
            status = 0;  /* invalid option */
        }
    }
    return status;
}


LUA_API int lua_getinfo(lua_State *L, const char *what, lua_Debug *ar)
{
    int status;
    Closure *f = NULL;
    CallInfo *ci = NULL;
    void *plight = NULL;
    lua_lock(L);
    if (*what == '>')
    {
        StkId func = L->top - 1;
        luai_apicheck(L, ttisfunction(func) || ttislightfunction(func));
        what++;  /* skip the '>' */
        if (ttisfunction(func))
            f = clvalue(func);
        else
            plight = fvalue(func);
        L->top--;  /* pop function */
    }
    else if (ar->i_ci != 0)    /* no tail call? */
    {
        ci = L->base_ci + ar->i_ci;
        lua_assert(ttisfunction(ci->func) || ttislightfunction(ci->func));
        if (ttisfunction(ci->func))
            f = clvalue(ci->func);
        else
            plight = fvalue(ci->func);
    }
    status = auxgetinfo(L, what, ar, f, plight, ci);
    if (strchr(what, 'f'))
    {
        if (f != NULL)
            setclvalue(L, L->top, f)
            else if (plight != NULL)
                setfvalue(L->top, plight)
                else
                    setnilvalue(L->top);
        incr_top(L);
    }
    if (strchr(what, 'L'))
        collectvalidlines(L, f);
    lua_unlock(L);
    return status;
}


/*
** {======================================================
** Symbolic Execution and code checker
** =======================================================
*/

#define check(x)        if (!(x)) return 0;

#define checkjump(pt,pc)    check(0 <= pc && pc < pt->sizecode)

#define checkreg(pt,reg)    check((reg) < (pt)->maxstacksize)



static int precheck(const Proto *pt)
{
    check(pt->maxstacksize <= MAXSTACK);
    check(pt->numparams + (pt->is_vararg & VARARG_HASARG) <= pt->maxstacksize);
    check(!(pt->is_vararg & VARARG_NEEDSARG) ||
          (pt->is_vararg & VARARG_HASARG));
    check(pt->sizeupvalues <= pt->nups);
    check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
    check(pt->sizecode > 0 && GET_OPCODE(pt->code[pt->sizecode - 1]) == OP_RETURN);
    return 1;
}


#define checkopenop(pt,pc)  luaG_checkopenop((pt)->code[(pc)+1])

int luaG_checkopenop(Instruction i)
{
    switch (GET_OPCODE(i))
    {
    case OP_CALL:
    case OP_TAILCALL:
    case OP_RETURN:
    case OP_SETLIST:
    {
        check(GETARG_B(i) == 0);
        return 1;
    }
    default:
        return 0;  /* invalid instruction after an open call */
    }
}


static int checkArgMode(const Proto *pt, int r, enum OpArgMask mode)
{
    switch (mode)
    {
    case OpArgN:
        check(r == 0);
        break;
    case OpArgU:
        break;
    case OpArgR:
        checkreg(pt, r);
        break;
    case OpArgK:
        check(ISK(r) ? INDEXK(r) < pt->sizek : r < pt->maxstacksize);
        break;
    }
    return 1;
}


static Instruction symbexec(const Proto *pt, int lastpc, int reg)
{
    int pc;
    int last;  /* stores position of last instruction that changed `reg' */
    last = pt->sizecode - 1; /* points to final return (a `neutral' instruction) */
    check(precheck(pt));
    for (pc = 0; pc < lastpc; pc++)
    {
        Instruction i = pt->code[pc];
        OpCode op = GET_OPCODE(i);
        int a = GETARG_A(i);
        int b = 0;
        int c = 0;
        check(op < NUM_OPCODES);
        checkreg(pt, a);
        switch (getOpMode(op))
        {
        case iABC:
        {
            b = GETARG_B(i);
            c = GETARG_C(i);
            check(checkArgMode(pt, b, getBMode(op)));
            check(checkArgMode(pt, c, getCMode(op)));
            break;
        }
        case iABx:
        {
            b = GETARG_Bx(i);
            if (getBMode(op) == OpArgK) check(b < pt->sizek);
            break;
        }
        case iAsBx:
        {
            b = GETARG_sBx(i);
            if (getBMode(op) == OpArgR)
            {
                int dest = pc + 1 + b;
                check(0 <= dest && dest < pt->sizecode);
                if (dest > 0)
                {
                    int j;
                    /* check that it does not jump to a setlist count; this
                       is tricky, because the count from a previous setlist may
                       have the same value of an invalid setlist; so, we must
                       go all the way back to the first of them (if any) */
                    for (j = 0; j < dest; j++)
                    {
                        Instruction d = pt->code[dest - 1 - j];
                        if (!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0)) break;
                    }
                    /* if 'j' is even, previous value is not a setlist (even if
                       it looks like one) */
                    check((j & 1) == 0);
                }
            }
            break;
        }
        }
        if (testAMode(op))
        {
            if (a == reg) last = pc;  /* change register `a' */
        }
        if (testTMode(op))
        {
            check(pc + 2 < pt->sizecode); /* check skip */
            check(GET_OPCODE(pt->code[pc + 1]) == OP_JMP);
        }
        switch (op)
        {
        case OP_LOADBOOL:
        {
            if (c == 1)    /* does it jump? */
            {
                check(pc + 2 < pt->sizecode); /* check its jump */
                check(GET_OPCODE(pt->code[pc + 1]) != OP_SETLIST ||
                      GETARG_C(pt->code[pc + 1]) != 0);
            }
            break;
        }
        case OP_LOADNIL:
        {
            if (a <= reg && reg <= b)
                last = pc;  /* set registers from `a' to `b' */
            break;
        }
        case OP_GETUPVAL:
        case OP_SETUPVAL:
        {
            check(b < pt->nups);
            break;
        }
        case OP_GETGLOBAL:
        case OP_SETGLOBAL:
        {
            check(ttisstring(&pt->k[b]));
            break;
        }
        case OP_SELF:
        {
            checkreg(pt, a + 1);
            if (reg == a + 1) last = pc;
            break;
        }
        case OP_CONCAT:
        {
            check(b < c);  /* at least two operands */
            break;
        }
        case OP_TFORLOOP:
        {
            check(c >= 1);  /* at least one result (control variable) */
            checkreg(pt, a + 2 + c); /* space for results */
            if (reg >= a + 2) last = pc; /* affect all regs above its base */
            break;
        }
        case OP_FORLOOP:
        case OP_FORPREP:
            checkreg(pt, a + 3);
            /* go through */
        case OP_JMP:
        {
            int dest = pc + 1 + b;
            /* not full check and jump is forward and do not skip `lastpc'? */
            if (reg != NO_REG && pc < dest && dest <= lastpc)
                pc += b;  /* do the jump */
            break;
        }
        case OP_CALL:
        case OP_TAILCALL:
        {
            if (b != 0)
            {
                checkreg(pt, a + b - 1);
            }
            c--;  /* c = num. returns */
            if (c == LUA_MULTRET)
            {
                check(checkopenop(pt, pc));
            }
            else if (c != 0)
                checkreg(pt, a + c - 1);
            if (reg >= a) last = pc;  /* affect all registers above base */
            break;
        }
        case OP_RETURN:
        {
            b--;  /* b = num. returns */
            if (b > 0) checkreg(pt, a + b - 1);
            break;
        }
        case OP_SETLIST:
        {
            if (b > 0) checkreg(pt, a + b);
            if (c == 0)
            {
                pc++;
                check(pc < pt->sizecode - 1);
            }
            break;
        }
        case OP_CLOSURE:
        {
            int nup, j;
            check(b < pt->sizep);
            nup = pt->p[b]->nups;
            check(pc + nup < pt->sizecode);
            for (j = 1; j <= nup; j++)
            {
                OpCode op1 = GET_OPCODE(pt->code[pc + j]);
                check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
            }
            if (reg != NO_REG)  /* tracing? */
                pc += nup;  /* do not 'execute' these pseudo-instructions */
            break;
        }
        case OP_VARARG:
        {
            check((pt->is_vararg & VARARG_ISVARARG) &&
                  !(pt->is_vararg & VARARG_NEEDSARG));
            b--;
            if (b == LUA_MULTRET) check(checkopenop(pt, pc));
            checkreg(pt, a + b - 1);
            break;
        }
        default:
            break;
        }
    }
    return pt->code[last];
}

#undef check
#undef checkjump
#undef checkreg

/* }====================================================== */


int luaG_checkcode(const Proto *pt)
{
    return (symbexec(pt, pt->sizecode, NO_REG) != 0);
}


static const char *kname(Proto *p, int c)
{
    if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
        return svalue(&p->k[INDEXK(c)]);
    else
        return "?";
}


static const char *getobjname(lua_State *L, CallInfo *ci, int stackpos,
                              const char **name)
{
    if (isLua(ci))    /* a Lua function? */
    {
        Proto *p = ci_func(ci)->l.p;
        int pc = currentpc(L, ci);
        Instruction i;
        *name = luaF_getlocalname(p, stackpos + 1, pc);
        if (*name)  /* is a local? */
            return "local";
        i = symbexec(p, pc, stackpos);  /* try symbolic execution */
        lua_assert(pc != -1);
        switch (GET_OPCODE(i))
        {
        case OP_GETGLOBAL:
        {
            int g = GETARG_Bx(i);  /* global index */
            lua_assert(ttisstring(&p->k[g]));
            *name = svalue(&p->k[g]);
            return "global";
        }
        case OP_MOVE:
        {
            int a = GETARG_A(i);
            int b = GETARG_B(i);  /* move from `b' to `a' */
            if (b < a)
                return getobjname(L, ci, b, name);  /* get name for `b' */
            break;
        }
        case OP_GETTABLE:
        {
            int k = GETARG_C(i);  /* key index */
            *name = kname(p, k);
            return "field";
        }
        case OP_GETUPVAL:
        {
            int u = GETARG_B(i);  /* upvalue index */
            *name = p->upvalues ? getstr(p->upvalues[u]) : "?";
            return "upvalue";
        }
        case OP_SELF:
        {
            int k = GETARG_C(i);  /* key index */
            *name = kname(p, k);
            return "method";
        }
        default:
            break;
        }
    }
    return NULL;  /* no useful name found */
}


static const char *getfuncname(lua_State *L, CallInfo *ci, const char **name)
{
    Instruction i;
    if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
        return NULL;  /* calling function is not Lua (or is unknown) */
    ci--;  /* calling function */
    i = ci_func(ci)->l.p->code[currentpc(L, ci)];
    if (GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
            GET_OPCODE(i) == OP_TFORLOOP)
        return getobjname(L, ci, GETARG_A(i), name);
    else
        return NULL;  /* no useful name can be found */
}


/* only ANSI way to check whether a pointer points to an array */
static int isinstack(CallInfo *ci, const TValue *o)
{
    StkId p;
    for (p = ci->base; p < ci->top; p++)
        if (o == p) return 1;
    return 0;
}


void luaG_typeerror(lua_State *L, const TValue *o, const char *op)
{
    const char *name = NULL;
    const char *t = luaT_typenames[ttype(o)];
    const char *kind = (isinstack(L->ci, o)) ?
                       getobjname(L, L->ci, cast_int(o - L->base), &name) :
                       NULL;
    if (kind)
        luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
                      op, kind, name, t);
    else
        luaG_runerror(L, "attempt to %s a %s value", op, t);
}


void luaG_concaterror(lua_State *L, StkId p1, StkId p2)
{
    if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
    lua_assert(!ttisstring(p1) && !ttisnumber(p1));
    luaG_typeerror(L, p1, "concatenate");
}


void luaG_aritherror(lua_State *L, const TValue *p1, const TValue *p2)
{
    TValue temp;
    if (luaV_tonumber(p1, &temp) == NULL)
        p2 = p1;  /* first operand is wrong */
    luaG_typeerror(L, p2, "perform arithmetic on");
}


int luaG_ordererror(lua_State *L, const TValue *p1, const TValue *p2)
{
    const char *t1 = luaT_typenames[ttype(p1)];
    const char *t2 = luaT_typenames[ttype(p2)];
    if (t1[2] == t2[2])
        luaG_runerror(L, "attempt to compare two %s values", t1);
    else
        luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
    return 0;
}


static void addinfo(lua_State *L, const char *msg)
{
    CallInfo *ci = L->ci;
    if (isLua(ci))    /* is Lua code? */
    {
        char buff[LUA_IDSIZE];  /* add file:line information */
        int line = currentline(L, ci);
        luaO_chunkid(buff, getstr(getluaproto(ci)->source), LUA_IDSIZE);
        luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
    }
}


void luaG_errormsg(lua_State *L)
{
    if (L->errfunc != 0)    /* is there an error handling function? */
    {
        StkId errfunc = restorestack(L, L->errfunc);
        if (!ttisfunction(errfunc) && !ttislightfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
        setobjs2s(L, L->top, L->top - 1);  /* move argument */
        setobjs2s(L, L->top - 1, errfunc);  /* push function */
        incr_top(L);
        luaD_call(L, L->top - 2, 1);  /* call it */
    }
    luaD_throw(L, LUA_ERRRUN);
}


void luaG_runerror(lua_State *L, const char *fmt, ...)
{
    va_list argp;
    va_start(argp, fmt);
    addinfo(L, luaO_pushvfstring(L, fmt, argp));
    va_end(argp);
    luaG_errormsg(L);
}

